Different Types of Fire Extinguishers and Their Uses
Reading Time: 4 minutes
By Anita B. Stone – Not only is it smart to keep fire extinguishers in your home, but it’s also the law in many states.
Many of us do not realize that a single fire extinguisher does not work on every type of fire. So, to protect yourself fully, especially on the homestead, you need to decide which rooms in your home need an extinguisher and ensure that you have the appropriate extinguisher for any potential fire. Plus, don’t forget to have your fire evacuation procedures in order.
Here is a brief explanation of the basic elements of fire. Briefly defined, there are five classes of fire:
*Class A is freely burning, combustible solid materials such as wood or paper.
*Class B is flammable materials such as liquid or gas.
*Class C is the energized electrical fire (energized electrical source serves as the ignitor of a *Class A or B fire if electrical source is removed, it is no longer a Class C fire)
*Class D is a metallic fire, such as titanium, zirconium, magnesium, sodium)
*Class K is a cooking fire, where animal or vegetable oils or fats create a fire.
Regardless of the type of fire, there will always be these same four elements present: fuel, heat, oxygen, and chain reaction.
The theory behind putting out a fire is that it can be extinguished by removing any one or more of the four elements.
For each class of fire, the fuel, heat source, and chain reaction vary, which is why you need different types of fire extinguishers. For example, a Class A fire can be safely extinguished with water, but a Class C fire cannot, as water would conduct the electricity and risk harm.
There are six main types of fire extinguishers including recent innovations:
ABC Powder Fire Extinguisher has many advantages as it is a multi-purpose extinguisher and is one of the most common extinguishers to have on the homestead.
A powder extinguisher sprays a fine chemical powder composed of monoammonium phosphate which acts to blanket the fire and suffocates it. Powder extinguishers are effective for Class A, B, and C fires since it is not an electrical conductor and it can break the chain reaction in a liquid or gas fire, something a water extinguisher cannot do.
Carbon Dioxide Fire Extinguisher is one of the cleanest types of extinguishers to us because it leaves no residue and requires no cleanup. The CO2 extinguisher does exactly what its name says, extinguishes CO2. It removes oxygen from the fire, effectively suffocating it of oxygen. It is perfect for use on Class B fires that involve flammable liquids and on electrical fires.
Wet Chemical Fire Extinguisher is a specialized type of extinguisher focused on Class K fires, those involving cooking media such as animal and vegetable fats or oils. This extinguisher contains a solution made up of potassium that that attacks the fires on two accounts. First, the liquid mist spray acts to cool the fire. Second, a thick soap-like substance forms, sealing the surface of the liquid to prevent re-ignition. It can also be used for Class A fires where materials such as wood or paper had caught fire.
Water Mist Fire Extinguisher is the most versatile of all fire extinguishers. It uses a new technology that works across most fires. This type of extinguisher releases microscopic water molecules that fight fires on many levels. First, because so much water is dispersed in such a microscopic fog-like form, the level of oxygen in the air is decreased, which helps to suffocate the fire.
Second, the water particles are drawn to the fire and therefore acts to cool it, reducing the temperature.
The best and most unique part about the water mist extinguisher is that minerals have been removed. So, it can actually be used on electrical fires because the water will not act as a conductor, as well as on burning liquids and gases where a standard water extinguisher could not be effective. A water mist extinguisher is safe and effective for use on Classes A, B, C, and K fires.
Foam Fire Extinguishers are suitable for Class A and flammable liquids of Class B, but not effective for gas fires. They spray a type of foam that expands when it hits the air and blankets the fire. This protection prevents the vapors from rising off the liquid to feed the fire, starving it of fuel. Because the foam is mixed with water, it has a cooling effect as well. This type of extinguisher is best for liquid fires, such as gasoline fires, but can also be used on Class A fires that involve combustibles like wood.
Clean Agent Fire Extinguisher is a selective type. Stored in liquid form, when it is sprayed and hits the air, it converts to its gas form which is non-conductive, safe for use while humans are present, leaves no residue, and has a very short atmospheric lifetime, making it eco-friendly. The gas, often composed of Halon, extinguishes fire by reducing the oxygen levels and impeding the chain reaction.
In choosing a fire extinguisher, make sure that you can easily lift what you select. Larger extinguishers may pack more power, but you must be able to use them properly. An extinguisher that you can’t easily and knowledgeably use is useless.
Learning how to use your fire extinguisher is imperative. Familiarize yourself with the directions so you will be prepared in case you need to put out a fire. Typically, fire extinguishers are fairly easy to use in the case of a fire. Most types operate using the ‘P.A.S.S.’ technique.
*P. Pull the pin on the fire extinguisher in order to break the tamper seal.
*A. Aim the fire extinguisher low with the nozzle pointed at the base of the fire.
*S. Squeeze the handle of the fire extinguisher to release the extinguishing agent.
*S. Sweep the nozzle from side to side while pointed at the base of the fire until it is extinguished.
It is recommended to keep at least one fire extinguisher on each level of your home. Make certain to keep the extinguishers handy where fires are more likely to start, such as in the kitchen and garage. If you own outbuildings, barns, and other structures, make certain you protect the property with the proper fire extinguisher. And make certain you place the extinguisher at the proper level for each location so everyone will know where it can be found when necessary.
Read the safety directions on each extinguisher, because there may be additional safety procedures on each one, depending on the type you use.
In summation, know your extinguishers, place them in proper locations, and know the types of fire in order to protect yourself.
Originally published in the January/February 2021 issue of Countryside & Small Stock Journal and regularly vetted for accuracy.